Analog Frequency Multiplier
PL560-xx VCXO Family
Figure 5: Diagram Representation of the Related System Inductance and Capacitance
DIE SIDE
- Cinternal = Based on AFM device
- Cpad = 2.0 pF, Bond pad and its ESD circuitry
- C11 = 0.4 pF, The following amplifier stage
PCB side
- LWB1 = 2 nH, (2 places), Stray inductance
- Cstray = 1.0 pF, Stray capacitance
- L2X (L4X) = 2x or 4x inductor
- C2X (C4X) = range (0.1 to 2.7 pF), Fine tune
inductor if used
•
There are two default variables that normally will not need to be modified. These are Cpad, and C11 and
are found in cells B22 and B27 of ‘AFM Tuning Assistant’, respectively.
•
LWB1 is the combined stray inductance in the layout. The DIE wire bond is ~ 0.6 nH and in the case of a
leaded part an additional 1.0 nH is added. Your layout inductance must be added to these. There are 2 of
these and they are assumed to be approximately symmetrical so you only need to enter this inductance
once in cell B23.
•
Enter the stray parasitic capacitance into cell B26. An additional 0.5 pF must be added to this value if a
leaded part is used.
•
Enter the appropriate value for Cinternal into B21 based on the device used (see column D). Use the ‘AFM
Tuning Assistant’ software to calculate L2X (and C2X if used) for your resonance frequency.
•
For 4X AFMs, repeat the same procedure in the L4X worksheet.
•
See the examples in the following section.
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Rev.:02-09-07 Page 6
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